05-31-2017, 06:50 PM | #1 |
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LSD or Wider Wheels/Tires?
The M2XXi has boat loads of torque especially with a tune, which mod do you do first- an LSD or bigger rubber?
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05-31-2017, 06:54 PM | #2 |
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Watch Engineering Explained. Tires are everything.
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05-31-2017, 07:04 PM | #3 | |
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and kind of the opposite for the tires... bigger tire will help quite a bit on a straight line but it won't do much if on the turn, the inside tire spinning and the outside wheel gets no torque without an LSD... do both |
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05-31-2017, 07:22 PM | #4 |
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Actually, I saw that episode. Great series. In this case, if I remember correctly, he was comparing horsepower improvements to tire improvements, but he oversimplified the issue describing tire improvements in terms of g loading, which I think can also be improved with an LSD. Point taken though.
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05-31-2017, 07:25 PM | #5 | |
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05-31-2017, 11:19 PM | #7 |
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I have a JB4 and an intake, so probably around 375/375 @ the wheels and had no problem cutting a 1.91 60', on stock PSS, so the reality is, these cars get off the line ridiculously well compared to other high powered RWD cars. I might go 255 when the rears wear out.
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06-01-2017, 04:31 AM | #8 |
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Street driving? LSD every time.
Despite what people think, an LSD will get you off the line quicker too, so it's not just for corners. But the transformation at having two wheels working together is a beautiful thing. Tyres, you replace anyway, so unless you need new ones now, don't throw away good ones for the sake of a width or two up. It doesn't make that much difference. |
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06-01-2017, 07:26 AM | #9 |
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Wouldnt worry about tires if you have the MPSS setup. If you're on RFT, I would replace those first.
Secondly, were you planning on going with 19" wheels when upgrading tires? I'm considering an LSD right now as well, had upgraded to wider 19" six months ago and I would say it's more aesthetically appealing than it is a substantial difference in performance (I had the stock MPSS setup). |
06-01-2017, 10:42 AM | #10 |
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My tuned M235i is running NT05 265/35x18 with a UTQG treadwear 200 on back axle without LSD. Just drove another M235i with OEM Michelin PSS 245/35x18 UTQG treadwear 300. I'll be placing an order for and installing a LSD as my next mod.
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06-01-2017, 11:38 AM | #11 |
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So, given MPSS tires on OEM rims and mainly for daily driving including spirited runs, I get the feeling the consensus is to first go the LSD route.
If so, I take it the M Performance LSD is the practical/conservative way to go, as opposed to a Quaife or similar? |
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06-01-2017, 12:12 PM | #12 | |
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Both types are good, but the Quaife is my preference. |
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06-01-2017, 12:15 PM | #13 |
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Wider tires are only indirectly related to better traction, and mostly in track conditions where tires are maxxed out (probably hurts handling a little in the wet). Going up to the near-racing compounds would be far more effective for traction, but it brings in the issue of crappy wet/cold performance (and high wear).
Contact patch area is a function of weight and psi, so wider tires just change the SHAPE of the patch, not really the area. Friction is a function of area times coefficient of friction, and it doesn't care about shape (in static load, or when they test 'g-force' road-holding on a circular track). Wider patches have advantages for racing - each part is only worked a short time per rev, then has more time to cool, and any road gaps or debris are only affecting part of the patch at any one time; they can also crutch poor suspensions, as there is usually less effect from extreme camber changes. On a street car, I really doubt you could distinguish the changes from a 20mm difference just by road feel (if, however, you just dropped $2k on wheels and tires, you damn sure notice how much better those 255s feel). You'll probably notice changes in wheel weight more than the tread width, so pay attention to that with wider setups. LSD is also only active at the limits, but probably more relevant for spirited street driving than a small increase in width; they wont do a thing for the g-load rating numbers (even if they do help handling) since that is never measured with wheel spinning. It is not really an option as a mod, but IMHO the king hell route to better traction is the X-drive. |
06-01-2017, 06:28 PM | #14 |
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You'd be surprised at how a car behaves during regular driving over uneven surfaces, slow turns, high speed stability, etc with an LSD. I drove a back to back with my buddy's m235 and mine with the LSD and his car was noticeably less connected to the road on launches, turn in/outs (8spd vs my 6spd) and slow driving on uneven roads (we have a lot in my parts). It may have been my M4 LCA's/TS's, but it felt more drivetrain related that day.
I'd say if you have PSS's, get the LSD next before new tires or wheels. That way you can't put it off any longer You'll thank me afterwards. Best mod that can be done to a non LSD performance driven vehicle, in my opinion. My friend just bought a Quaife off of a forum member here, for his M235i after seeing how different our cars felt. He's pretty stoked to say the least. If I could choose, I'd take a Quaife over the M-Performance unit, but not complaining about what I have at all. Just have always used Quaife's in my VAG cars and never let me down. Great resale too My $.02 D |
06-01-2017, 07:40 PM | #15 | |
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06-01-2017, 07:48 PM | #16 |
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I appreciate the input folks. Any other opinions on brand, type (clutch, gear, etc) LSD you all like. Thanks again!
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06-01-2017, 08:27 PM | #17 |
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Do the LSD. I'm in an M2 now and it makes a world of difference. It's a night and day transformation in the driving demeanor of the car. Keep in mind, I loved my 235i, but the LSD in the M2 is intoxicating.
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06-02-2017, 06:37 AM | #18 |
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Same experience here. I put in a Wavetrac LSD with an altered final drive ratio. Transformed the car and it now generates gobs of smiles on the street . Also went back from a 255 to a 245 in the rear. Breaking traction may not be great on the track but it adds to the fun on the street.
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06-02-2017, 09:16 AM | #20 |
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I don't feel that the M240i is a confidence inspiring in the twisties as my e46 M3C was, even with the OEM MPSS. I do wonder if the M Performance LSD would help.
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06-02-2017, 05:56 PM | #21 |
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Do you have stock suspension? I found just the addition of Dinan springs to make the car feel way more planted and much less body roll. That may help.
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06-02-2017, 07:36 PM | #22 |
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I suppose anything other than the M Performance LSD has BMW warranty implications. Any opinions there?
Also, it looks like VAC Motorsports is the sole importer in the US of Quaife LSDs. Are they the only option for retail or can you order direct from Quaife? Other options? |
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